Target mounting for scan converter tubes

ABSTRACT

A target mounting arrangement for double-ended scan converter tubes is disclosed. A target assembly is provided having internal structure to support a storage mesh assembly centrally of the arrangement with read and write collector and collimater assemblies on opposed sides thereof. A support is secured to the assembly and comprises an annular radially outwardly directed flange which is interposed between two segments of the tube and is sealingly secured thereto. The support flange is preferably of a kovar material which can be readily sealed to the abutting glass tube ends. Strength, rigidity, and improved manufacturing economies result.

United States Patent Inventor Katsuyoshi Fuiimoto Carlsbad, Calif.

Appl. No. 775,073

Filed Nov. 12, 1968 Patented Jan. 5, 1971 Assignee Hughes Aircraft Company Culver City, Calif. a corporation of Delaware TARGET MOUNTING FOR SCAN CONVERTER TUBES Primary Examiner-Robert Segal Attorneys-James K. Haskell and Robert H. Himes ABSTRACT: A target mounting arrangement for doubleended scan converter tubes is disclosed. A target assembly is provided having internal structure to support a storage mesh assembly centrally of the arrangement with read and write collector and collimater assemblies on opposed sides thereof. A support is secured to the assembly and comprises an annular radially outwardly directed flange which is interposed between two segments of the tube and is sealingly secured thereto. The support flange is preferably of a Kovar material which can be readily sealed to the abutting glass tube ends. Strength, rigidity, and improved manufacturing economies result.

TARGET MOUNTING FOR SCAN CONVERTER TUBES The invention is directed to a mounting arrangement for a target assembly having particular utility in double-ended scan converter tubes.

Prior art target arrangements for double-ended scan converter tubes have characteristically been supported and mounted in the tube by a multilegged spokelike structure frequently fonned of glass material. The glass spokes were placed in abutting relationship to the inner peripheral surface of the glass tube envelope and a glass-to-glass seal or connection was provided. This was frequently accomplished by a welding operation in the final tube assembly stages which characteristically could result in accidental weld splash falling on the mesh target creating unwanted damage thereto. In addition to assembly difficulties, prior art structures inherently had internal stresses created therein which, on occasion,

would create radial compressive forces which could involve damage to the storage ring mesh structure rendering the tube inoperative or creating unsatisfactory operation.

Accordingly, it is a primary object of the present invention to provide a simplified target structure which may be easily and quickly assembled to a double-ended scan converter tube thus avoiding the difficulties of prior art structures and assembly methods.

It is a further object of the invention to provide a mounting arrangement for a double-ended scan converter tube target structure which will provide in service ruggedness and avoid damage to the target structure when the tube per se is used in service applications which may involve extreme vibration or become more apparent in the course of the following description and from an examination of the related drawings, wherein:

FIG. 1 is an endelevational view of a typical target assembly of the invention;

FIG. 2 is a sectional view taken along lines 2-2 of FIG. 1; and

FIG. 3 is a detailed view of the support flange used in the invention. g

As is well known in the art, double-ended scan converter tubes are utilized to convert received electromagnetic signals having a determined, usually slow, frequency or raster rate of scan to another frequency of raster rate usually faster than the received rate. For example, signals from satellites or remote stations having a slow raster rate are sometimes converted to a signal or output which approaches that normally used in television which is more readily adaptable to the human eye in that flicker does not appear to be present. This conversion of signal rate is accomplished by providing a storage target which is first exposed to the electron beam of a writing gun and retains, by variation and charge pattern thereon, the modulated signal received from the remote source. The same target is exposed to another electron beam from what is commonly called the reading gun which scans the target at a different raster rate and creates output signals from the storage charge pattern thereon directly related to the modulated input signals of the writing gun only now at a higher frequency or faster raster rate. It is in this mode of operation that scan converter tubes have utility in the art.

Needless to say, the target assemblies that are structured to accommodate this function must be carefully manufactured and must be carefully positioned in the scan converter tube so that functional alignment between the various electron beams utilized may be easily maintained. Additionally, the targets of necessity should be mounted to resist mechanical impact or vibratory motion or any shock, for that matter, to prevent further misalignment while in service which would lead to unsatisfactory scan converter tube operation.

Directing attention to the FIGS. the present invention provides a unique mode of mounting a storage assembly for a double-ended scan converter tube within the tubes structure. The mounting assembly comprises an annular support flange indicated generally at 10 which is also shown in detail in FIG. 3 and which has a radially directed segment 12 and an inner peripherally arranged axially directed segment 14. The support flange 10 is physically secured, in any conventional manner, to a first collimater assembly 16 which is a cupshaped element having an opening 18 centrally formed therein. The axial 14 of the support flange is used to make this connection.

An annular ring 20 is secured to the forward aspect of the read collimater assembly 16, again, in any conventional manner, and provides a mode of supporting a meshlike collector electrode 22 which covers the entire opening in the ring 20 and serves as a means of collecting electrons during tube operation as is well understood by those skilled in the art. A plurality of pins 23 are provided in small openings in the radial segment 12 of the support flange 10 which project longitudinally and have their inner ends secured to the read collimater assembly 16. As many pins 23 as desired may be peripherally located around the entire arrangement, for example, in the preferred embodiment shown, six pins are used. A storage mesh assembly, well known in the art, is positioned adjacent the collector mesh 22, said storage mesh assembly being indicated by the numeral 24 and is secured to an annular ring 26 having a central opening 27 therein. A storage mesh 25 of the assembly 24 covers the entire opening 27.

Adjacent the storage mesh assembly 24 a write collimater assembly indicated generally at 28 is provided and comprises a cup-shaped metallic element 30 having a central opening therein and an annular ring 32, also with a central opening, secured to its inwardly directed aspect. The ring 32 provides a convenient mode for mounting a collector mesh 34 which covers the entire opening of the ring 32 as well as the opening in the cup-shaped element 30. Again, a plurality of mounting pins 36 are secured to the write collimater assembly 28 and are in alignment with the mounting pins 23 secured to the read collimater assembly referred to above. In addition, mounting pins 38 are secured to the annular ring 26 which supports the storage mesh 24, the pins 38 also being in physical alignment with the pins 23 and 36. As a result of the securing of the respective mounting pins to their respective related structure, it will be apparent that a plurality of weld or soldered beads 39, 39 may be used to secure the respective components in the desired physical relation to each other.

As described above, it will be apparent that a complete target assembly has been provided for a double-ended scan converter tube. Referring specifically to FIG. 2, it will be seenthat the support flange l0 and particularly its radially directed segment 14 is arranged to be interposed between two kovar segments of the tube as fragmentarily shown at 40 and 42. Kovar segments 40 and 42, of course, firmly engage and receive the flange segment interposed therebetween. In a preferred embodiment of the invention, the flange segment 12 is made of metal material which may be readily sealed to the kovar and thereby provide a fixed or rigid mounting of the entire assembly within the double-ended scan converter tube. In addition, snubber arrangements which are nothing more than cantilevered spring elements and indicated by the number 44 FIG. 1, may be provided and secured to the write collimater assembly 28 to abut the inner surface of the glass tube 42 and provide further support for this structure.

From the above description, it will be apparent that a target assembly for a double-ended scan converter tube which provides inherent design ruggedness and readily lends itself to uniformity of target suspension in production runs in this type of tube has been disclosed. With appropriate jigging or other fixturing, tube assembly, utilizing the target structure disclosed, is enhanced and the efficiency thereof increased. The structure disclosed also eliminates the spot welding necessary to mount the prior art target structures with its consequent damage to target structures as a result of weld splash.

The invention as disclosed is by way of illustration and not limitation and may be subject to various modifications all within the spirit and scope thereof.

I claim:

1. A mounting structure for an assembly including a storage target, a collimating structure, and a collector structure of a scan converter tube having an envelope with a longitudinal .axis, said mounting structure comprising an annular metal gitudinal axis, opposed surfaces of said flange being sealed in an electrode annulus disposed inside said inner portion of said flange and having an inwardly turned portion for supporting said collector structure, said storage target and said collimat ing structure being positioned on one side thereof in the order named adjacent to and coextensive. with said collector structure; no less than three sets of three pins aligned parallel to said longitudinal axis in spaced relationship around and attached to the respective outer peripheries of said collector structure, storage target and collimating structure; and first and second dielectric beads sealcd to adjacent pins in each of said sets thereby to insulatively support said storage target and said collimating structure relative to said collector structure. 

1. A mounting structure for an assembly including a storage target, a collimating structure, and a collector structure of a scan converter tube having an envelope with a longitudinal axis, said mounting structure comprising an annular metal flange extending outwardly from the periphery of said assembly with an inner portion being turned parallel to said longitudinal axis, opposed surfaces of said flange being sealed in abutting relationship to adjacent segments of said envelope; an electrode annulus disposed inside said inner portion of said flange and having an inwardly turned portion for supporting said collector structure, said storage target and said collimating structure being positioned on one side thereof in the order named adjacent to and coextensive with said collector structure; no less than three sets of three pins aligned parallel to said longitudinal axis in spaced relationship around and attached to the respective outer peripheries of said collector structure, storage target and collimating structure; and first and second dielectric beads sealed to adjacent pins in each of said sets thereby to insulatively support said storage target and said collimating structure relative to said collector structure. 